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Diamond Council of America © 2015 Compendium The Diamond Course ND OL 2015

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Diamond Council of America © 2015

Compendium

The Diamond Course

ND OL 2015

The Diamond CourseCompendium

Table of ConTenTs

The 4C’s in Brief .................................................................1

Carat Weight .......................................................................3

Clarity .................................................................................4

Color ...................................................................................6

Cut Shape and Style ............................................................9

Cut Quality .......................................................................12

Treatments, Synthetics and Simulants ...............................16

Properties and Formation ................................................20

Deposits, Sources and Mining ..........................................24

The Diamond Industry ......................................................27

Diamond Cutting ...............................................................30

Diamond Magic and Romance .........................................32

Durability and Care ..........................................................35

The Diamond Course Compendium

Gem Profiles

Photo courtesy Diamond Promotion Service.

The 4Cs in Brief

The Diamond Course Compendium 1

THE 4Cs IN BRIEF

• Everydiamondisunique,butalldiamondshavecertaincharacteristicsthataffecttheirvalue.Thesecharacteristicsareknownasthe4Cs.Theyarecaratweight,clarity,color,andcut.

Carat Weight • Diamondsareweighedincarats.Onecaratequals1/5gram,andisdividedinto100points.• Diamondsareweighedtoanaccuracyof1/2point(or5/1,000carat).

Clarity• Clarityisadiamond’sdegreeoffreedomfromblemishesandinclusions.Blemishesaresurface

irregularitiessuchasscratches.Inclusionsareinternalfeaturessuchastinycrystalsofotherminerals.Bothtypesoffeaturesarealsoknownasclaritycharacteristics.

• Almostalldiamondshaveclaritycharacteristics.Thefewerandlessprominentthecharacteristicsare,thehighertheclaritygradeis.Inmostcases,claritycharacteristicshavelittleornoeffectonadiamond’sappearance.

2 The Diamond Course Compendium

Color• Diamondsoccurinawidevarietyofcolors,butmostrangefromnearcolorlesstolightyellow,

brown,orgray.Althoughabsolutelycolorlessdiamondsareveryrare,theyareconsideredpartofthenormalmarketrange.

• Diamondswithnaturalcolorsoutsidethenormalrangeareclassifiedasfancycolor.Theseincludedeeperyellows,browns,andgrays,andallshadesofothercolors.

• Withinthenormalmarketrange,thelesscoloradiamondhas,thehigheritscolorgradeis.

Cut• Thetermcutoftenreferstoadiamond’sshapeandfacetingstyle.Themostpopularcutshapeand

styleistheroundbrilliant.Allothershapesandstylesareclassifiedasfancyshapesorfancycuts.Popularfancyshapesincludetheemeraldcut,heart,oval,marquise,pear,andprincess.

• Cutqualityisdeterminedbyadiamond’sproportions,symmetry,andpolish.Proportionsaretherelativesizesandanglesofthediamond’spartsandfacets.Symmetryistheprecisionofthecutdesign’sexecution.Polishisthesmoothnessandlusterofthediamond’ssurfaces.

The 4Cs and Value • Caratweight,clarity,andcolorreflectadiamond’snaturalrarity.Thelargerthediamondandthe

higheritscolorandclaritygrades,thegreateritsrarityandvalueis.• Cutisthehumancontributiontodiamondvalue.Thechoiceofcutshapeandstyleisamatterof

personalpreference.Cutqualityreflectsthecareandskillthatwereinvolvedintransformingtheroughcrystalintoasparklinggem.Cutqualityisalmostalwaysthetopfactorinadiamond’sbeauty.

• Adiamond’svalueisdeterminedbyallofthe4Cs.Beautyisessentialandraritycanhavegreatmeaning.Therefore,eachCshouldbeconsideredinadiamondpurchase.

The 4Cs in Brief

CaraT WeighT

The Diamond Course Compendium 3

CARAT WEIGHT Weight Units and accuracy• Thestandardunitofweightfordiamondsisthemetriccarat,whichequals1/5gram.Incommon

USmeasurements,onecaratequalsapproximately7/1,000ounce.Forgreateraccuracy,thecaratissubdividedinto100equalpartscalledpoints.

• Diamondsareusuallyweighedwithelectronicscales,whichhaveanaccuracyof1/10point(or1/1,000carat).

• IntheUS,diamondweightisusuallymeasuredto1/10pointandroundedtothenearestwholepoint.Forexample,aweightof0.995to1.004caratsisroundedto1.00carat.Thatmakestheaccuracy1/2point(or5/1,000carat)–about35millionthsofanounce.

Weight and Value• Caratweight’seffectonvalueisbasedonnaturalrarity.A1-caratdiamond,forexample,ismuch

rarerthantwo1/2-caratdiamondsofcomparablequality.Asaresult,thelargerdiamondismoreexpensivethanboththesmallerdiamondsaddedtogether.

• Differencesinrarityarereflectedintheper-caratpricesofdiamonds.Per-caratpriceisthecostforeachcaratofadiamond’sweight.

CLariTY

The Diamond Course Compendium 4

CLARITYClarity Characteristics• Clarityisadiamond’sdegreeoffreedomfromblemishesandinclusions.Blemishesaresurface

irregularitiessuchasscratches.Inclusionsareinternalfeaturessuchastinycrystalsofotherminerals.Bothtypesoffeaturesarealsocalledclaritycharacteristicsoridentifyingcharacteristics.

• Claritycharacteristicscomefromeventsinthelifeofadiamond.Manyarebyproductsofthediamondcrystal’sgrowthwithintheearth.Somecanbecausedduringthediamond’sjourneytothesurface.Thestressesofmining,processing,andcuttingmaycreateothers.

• Claritycharacteristicscanhavebenefits.Theyhelptoseparatenaturaldiamondsfromsyntheticsandsimulants.Likeaperson’sindividualfeatures,theyalsomakeadiamonduniqueandidentifiable.

Clarity grading• Toevaluateclarity,askilledgraderexaminesthediamondsystematicallyusing10-power(10x)

magnificationandspeciallighting.• Gradersassessclaritycharacteristicsbyfivecriteria–size,number,nature,position,andcolor.• Afterfindingandassessingthediamond’sclaritycharacteristics,thegraderassignsaclaritygrade

thatreflectstheirvisibility.Thegraderalsoconsiderswhetherthecharacteristicsmightaffectthediamond’snormalappearanceoritsdurability.

• TheGemologicalInstituteofAmerica(GIA)developedthemostwidelyuseddiamondclaritygradescale.Thefollowingtablesummarizesthegrades.

5 The Diamond Course Compendium

GIA Grade Abbrev Description*flawless fl no inclusions or blemishes visible at 10x.

internally flawless if no inclusions and only minor blemishes visible at 10x.

Very, Very slightly included VVs1 Minute inclusions extremely difficult to see at 10x.

VVs2 Minute inclusions very difficult to see at 10x.

Very slightly included Vs1 Minor inclusions fairly difficult to see at 10x.

Vs2 Minor inclusions fairly easy to see at 10x.

slightly included si1 noticeable inclusions easy to see at 10x.

si2 noticeable inclusions very easy to see at 10x.**

included i1 significant inclusions usually visible without magnification.

i2 significant inclusions easily visible without magnification.

i3 significant inclusions obvious without magnification; may also threaten durability.

CLariTY

* Allgradedescriptionsarebasedonaskilledgraderworkingwithpropermagnificationandlighting.** AsmallpercentageofSIdiamondshaveinclusionsthatcanbeseenwithoutmagnification.Some

organizationsgradethesediamondsSI3,butGIAdoesnotusethatgrade.

Clarity, Value, and Beauty • Clarity’seffectonvalueisbasedonnaturalrarity.Mostdiamondshaveclaritycharacteristics.The

fewerandlesssignificantthecharacteristicsare,thehighertheclaritygradeandtherarerandmoreexpensivethediamondis.

• Onlyabout2%ofallgemqualitydiamondsareFlawless.VVSisthehighestgradenormallyseeninjewelrystores,andmanyfinediamondsareintheVStoSIrange.

• Inmostcases,thereisnodirectlinkbetweenclarityandbeauty.Undermagnification,aVSdiamondmayappearflawlesstosomeonewhoisnotanexpert.EvenSIcharacteristicsarerarelyvisiblewithoutmagnification,sotheyhavelittleornoeffectonthediamond’sappearance.

• Decisionsaboutclarityoftendependonpersonalpriorities.Forthosewhoarequality-conscious,rarityandthehighstandardsofclaritygradingcanbeveryimportant.Toothers,gradedistinctionsdonotmattermuch,andthemainconsiderationisthediamond’sbeautyandindividuality.

• Mostpeoplefeelthathighclarityismoreimportantfordiamondsinringsthaninothertypesofjewelry.Thisisbecauseringsoftenreceivecloserscrutinyfromfamily,friends,andacquaintances.Rings–especiallyforengagements,weddings,andanniversaries–alsocarrydeepemotionalsymbolism.

COLOr

The Diamond Course Compendium 6

COLORThe Diamond Palette• Manypeoplethinkofdiamondsasbeingcolorlessgems,butdiamondsactuallyoccurinawide

rangeofcolors.Oneoftheworld’smostfamousdiamonds–theHope–isdarkblue.• Inadditiontocolorless,thediamondpaletterunsthroughblue,green,yellow,orange,red,pink,

purple,violet,brown,andgray.Italsoincludesblackandwhite.Manydiamondcolorscanvaryfromfainttointense.Onecolorthatisnotinthediamondpaletteisdeep"emerald"green.

• Mostdiamondsrangefromnearcolorlesstolightyellow,brown,orgray.Absolutelycolorlessdiamondsareveryrare,buttheyareconsideredpartofthenormalmarketrange.

• Diamondswithnaturalcolorsoutsidethenormalmarketrangeareclassifiedasfancycolor.Theseincludedeeperyellows,browns,andgrays,plusallshadesofothercolors.

• Diamondsarecolorednaturallybytracesofelementssuchasnitrogen,bydistortionsinthecrystalstructure,orbyacombinationofbothfactors.Artificialtreatmentscanalsoadd,subtract,orchangethecolorindiamonds.

Color grading – normal range • Tojudgethecolorofadiamondinthenormalmarketrange,thegradercomparesittoother

diamondsthathavebeenlaboratorygradedespeciallyforthispurpose.Thecomparisondiamondsareknownasmasterstones.

• Colorgradingisperformedundercarefullycontrolledconditions.Gradersturndiamondsandmasterstonesupsidedowntominimizereflections.

• Themasterstones,controlledconditions,andviewingdirectionsenablegraderstomakeveryprecisecolordistinctions.

• TheGemologicalInstituteofAmerica(GIA)developedthemostwidelyusedcolorgradescale.ItrunsfromD(colorless)throughZ(lightyellow,brown,orgray).Eachgraderepresentsacloselydefinedrangeratherthanasingle,specificcolor.

Photo courtesy Argyle.

7 The Diamond Course Compendium

— TheDgradeisabsolutelycolorless.

— TheEandFgradesarevirtuallycolorless.DifferencesbetweenD,E,andFaresoslight,onlyexpertscanseethemevenwhenthediamondsareunmounted.

— DiamondsintheG,H,I,andJgradesarenearcolorless.Theynormallyappearcolorlesswhentheyaremountedinjewelry.

— IngradesK,L,andM,diamondsarefaintlytinted.Thoseunder1/2caratusuallylookcolorlesswhenmounted,butlargerdiamondsmayshowaslighttint.

— IngradesNthroughZ,thelighttintbecomesincreasinglyvisible.

— DiamondsdarkerthanZarefancycolor.

Color grading – fancy Colors • Gradingproceduresforfancycolorsaresimilartothosefordiamondsinthenormalmarketrange.

Fancycolordiamondsaregradedface-up,however,becausethatistheonlywaytogetanaccurateimpressionofthecolor.

• Fancycolorsareanalyzedintermsofthreecomponents–hue,tone,andsaturation.— Hueisthecolor’sbasiccategory–red,yellow,green,blue,andsoforth,plusmixturessuchas

reddishorangeandblue-green.— Toneisthecolor’slightnessordarkness.— Saturationisthecolor’sstrengthandpurity.

• Basedonthecombinationoftoneandsaturation,theGemologicalInstituteofAmerica(GIA)usesthefollowingtermstodesignatethegradesoffancycolordiamonds:

faint Very Light Light fancy Light fancy fancy intense fancy Dark fancy Deep fancy Vivid

Thesegradesareadjustedtoreflecttherarityofdifferentcolors.

COLOr

The Diamond Course Compendium 8

Color, Value, and Beauty • Color’simpactonvalueislinkedtonaturalrarity.Withinthenormalmarketrange,lesscolor

equateswithgreaterrarityandvalue.• Onlyasmallfractionofdiamondsinthenormalrangearecolorless.Manyofthediamondssoldin

theUSrangefromGtoL.• Comparedtodiamondsinthenormalmarketrange,mostfancycolorsarerare.Therearemajor

differencesintheraritiesofdifferentcolors,however.Yellow,brown,andgrayareleastrare.Pink,green,andblueareveryrare,andredisextremelyrare.Soarepurepurpleandorange.

• Decisionsaboutcolorcandependonbudgetandpersonalpriorities.Adiamondofanycolorgradecanbebeautiful,andmanypeoplefeeldiamondsthatshowcolorhaveawarmappeal.Ontheotherhand,whilecolordistinctionsmaybesubtle,theyareapparenttotheexperteye.Trulycolorlessdiamondsareextremelyrare,andforcenturiestheyhavehadspecialstatusandsymbolism.

added facts about Color • Thelargerthediamond,themoreobviousanycolorwillbe.• Coloriseasiertoseeinsomecutstylesthaninothers.Forexample,anH-coloremeraldcut

diamondwillusuallyshowmorecolorthanaroundbrilliantofthesamegrade.• Cutqualitycanalsoaffectcolorappearance.Lowcutqualitycanmakealightyelloworbrowntint

moreobvious.• Colortendstobescrutinizedmoreinringsthaninothertypesofjewelrysuchaspendantsor

earrings.• Yellowgoldmasksfainttracesofyelloworbrownandenhancesdarkershadesofthesecolors.

Platinumandwhitegolddramatizecolorlessdiamondsandmostfancycolors,butcanmakeyelloworbrowntintsstandoutlessflatteringly.

COLOr

The Diamond Course Compendium 9

CUT shaPe anD sTYLe

CUT SHAPE AND STYLE

• Thetermcutisoftenusedtodescribeadiamond’sshapeandfacetingstyle.• Formanypeople,cutshapeandstyleispartofthementalimageofadiamond.Adiamond’sshape

canalsocontributetothemessagesadiamondsendsaboutthepersonwhogivesorwearsit.

Defining features • Mostdiamondcutshavetwomainparts:thecrownandthepavilion.Thecrownistheupperpart,

andthepavilionisthelowerpart.Thegirdleiswherethecrownandpavilionmeet.• Adiamond’sshapeisthegirdleoutlineasitisseenface-up,whenthediamondisset.• Acut’sstyleisdeterminedbytheshapesofitsfacetsandthepatterninwhichthefacetsare

arranged.(Facetsaretheflatgeometricsurfacesthatarepolishedonthediamond.)• Therearethreebasicstylesofcut–brilliantcut,stepcut,andmixedcut.

— Brilliantcutshavemostlykite-shapeandtriangularfacetsarrangedinaradialpattern.— Stepcutshavemostlyrectangularfacetsarrangedinrows.— Mixedcutshaveacombinationofbrilliantandstepfacets.

The round Brilliant Cut• Theroundbrilliantisthetop-sellingdiamondcutaroundtheworld.Itsdesignhasevolvedover

hundredsofyears,alongwithcuttingtechnology,scientificunderstandingoflight,andmodernappreciationofdiamond’sbeauty.

10 The Diamond Course Compendium

• Theroundbrilliantproduceshighweightyieldfrommostdiamondcrystals.Itcanalsomaximizediamond’sbrilliance,dispersion,andscintillation.

• Aroundbrilliantcuthasatotalof57or58facets–33onthecrown,and24or25onthepavilion,dependingonwhetherornotthereisaculet(atinyfacetatthebottom).Thegirdleisnormallypolishedsmooth,butitmaybefacetedorleftunpolished.

Classic fancy shapes • Anycutshapeandstyleotherthantheroundbrilliantisconsideredafancyshapeorfancycut.

Classicfancyshapesincludetheemeraldcut,oval,pear,heart,marquise,andprincess.• Theemeraldcutisthemostpopularstyleofdiamondstepcut.Ithasarectangularorsquareoutline

withbeveledcorners.Therearenormally58facets–25onthecrown,25onthepavilion,and8aroundthegirdle.

• Manyotherclassicfancyshapesareadaptationsoftheroundbrilliantcut.Thedesignisessentiallythesame,butfacetshapesmaybemodifiedandthenumberorarrangementoffacetscanvarytofitthegirdleoutline.

• Theprincesscutisoneofthemostpopularfancyshapes.Itissquareorrectangular(non-beveledcorners),withstraightsidesandbrilliant-stylefaceting.Insomemarkets,theprincesscutrivalstheroundbrilliantinpopularity.

Branded Diamond Cuts • Technology,science,andcreativityhaveproducedmanycut

shapesandstylesinadditiontothestandardroundbrilliantandclassicfancyshapes.Noveltycutsincludeflowers,butterflies,fish,horseheads,crosses,stars,halfmoons,etc.Todaytherearealsoagrowingnumberofbrandedcuts.

• Brandedcutsareavailablefromthefirmsthatdevelopedthemorlicensedtherighttoproducethem.Manyaretrademarkedorprotectedbycopyright.Atruebrandhasdistinctivecharacteristics.

• Fromatechnicalstandpoint,brandeddiamondcutsfallintotwobroadcategories–creativecutsandidealcuts.Manycreativecutsarebasedontraditionaldesigns,withchangesinthestyle,arrangement,ornumberoffacets.Idealcutsaimatperfectingthedesignandexecutionoftheroundbrilliant.Overthelastcoupledecades,idealcutshavegainedinpopularity,andtheynowrepresentasizablepercentageofthemarket.

CUT shaPe anD sTYLe

Photo courtesy Criss-cut™.

CUT shaPe anD sTYLe

The Diamond Course Compendium 11

The rationale of Cut • Adiamond’scutshapeandstylearechosentoproducemaximumbeautyandvaluefromtherough

diamondcrystal.• Toobtaingoodweightyield,cuttersoftenbasethecut’sshapeontheoriginalshapeofthediamond

crystal.• Clarityissometimesafactor.Thecuttermaychooseaparticularshapeinordertoeliminatelarge

inclusionsthatexistintheroughcrystal.Thecomplexreflectionsinbrilliantsmakeclaritycharacteristicslessnoticeable,whilethesimplerreflectionsofstepcutscanemphasizethelackofcharacteristicsinhighclaritydiamonds.

• Colorcanbeaconsideration.Theintricatereflectionsinbrilliantsmakelighttintsofcolorlessvisible.Colorlessnessisofteneasiertoappreciateinstepcutsandcertainbrandedcuts.

• Decisionsaboutcutshapeandstylecanalsoinvolveaesthetics,customerappeal,andmarketdemand.Diamondslargerthan4or5caratsareoftencutintofancyshapesbecausemanypeoplefeelthatlargeroundsaretooshowy.

shape, style, and Cost • Threefactorsaffectthecostofanyshapeorstyle–weightyieldfromrough,thelaborexpenseof

cutting,andoverallmarketdemand.• Roundbrilliantsproducehighweightyieldfrommostdiamondcrystals,butcuttingthemtoprecise

standardsusuallymeanssacrificingweightforbeauty.Italsotakesextralabor.Thedemandforroundbrilliantsisalwaysstrong.

• Fancyshapesareoftencutfromspeciallyselectedcrystals,sotheynormallyresultinhighweightyield.Cuttinglargefancyshapesrequiresgreattimeandskill,whichaddtothelaborcost.

• Emeraldcutsandothersquareorrectangularshapestypicallyretainthemostweightofallcuts.• Manybrandedcutsaremorecostlybecauseoftheirlimitedavailabilityandtheextralaborthat

goesintothem.

CUT QUaLiTY

The Diamond Course Compendium 12

CUT QUALITY Cut and Beauty • Cutqualityincludesthreefactors–proportions,symmetry,andpolish.

— Proportionsaretherelativesizesandanglesofthediamond’spartsandfacets.— Symmetryistheprecisionofthecutdesign’sexecution.— Polishisthesmoothnessandlusterofthediamond’ssurfaces.

• Awell-cutdiamondgathersandconcentrateslightfrommanydirections,thenreflectsthatlightoutwardagaintodazzletheeyesofbeholders.Thisopticalperformancecanbedescribedintermsofthreecomponents–brilliance,dispersion,andscintillation.— Brillianceisthetotalofwhitelightthatisreflectedfromthediamond’ssurfaceandinterior.— Dispersionistheseparatingofwhitelightintospectralhues.— Scintillationisthesparkleofbrightreflectionsthatcanbeseenasthediamond,thelightsource,

ortheobservermoves.• Whenproportions,symmetry,andpolisharecombinedeffectivelyandcutqualityisatthehighest

level,oneresultissuperioropticalperformance.Producingthistakesskilledeffort.Italsorequiressacrificingmuchoftheroughdiamondcrystal’sweight.

Proportions • Proportionsarethefoundationofadiamond’sopticalperformance.• Forroundbrilliantcuts,keyproportionsincludetotaldepth,tablesize,crownangle,paviliondepth,

girdlethickness,andculetsize.• Anaddedproportionconsiderationforfancyshapesistheattractivenessoftheshapeitself.This

partlydependsontherelationshipbetweenlengthandwidth.Alsoimportantisshapeappeal.Thisincludesfeatureslikeattractivelybeveledcornersonemeraldcutsandpleasinglyroundedcurvesonovals,pears,hearts,andmarquises.

Photo courtesy The Hearts On Fire Company.

• Whenawellcutdiamondissetinjewelry,lightstrikesitscrownfrommanydifferentangles.Somelightreflectsfromthesurface;therestentersthediamondandreflectsinternallyfromthepavilion.Ahighpercentagethenexitsthroughthecrown,travelingindirectionswhereitislikelytobeseen.Relativelylittlelightislostorwasted.

• Outofallthepossiblecombinationsofproportions,onlyasmallnumbercreatethebestopticalperformanceinroundbrilliantcuts.Theseareknownasidealproportions.Cuttingadiamondtoidealproportionsmayrequiregivingupmorethanhalfthecrystal’soriginalweight.Thisislikelytoresultinacomparativelyhighper-caratprice.

• Cutterscanvaryproportionstoobtainhigherweightyield.Ifadiamondisnotproperlyproportioned,however,agreatdealoflightescapesthroughthepavilion,orleavesthecrowntravelingindirectionsawayfromobservers.Dependingonthevariations,thediamondmaythenlookdarkorglassy.Extremeweight-savingproportionscanreducethediamond’sdurability.

• Thoughcurrentlybeingresearched,idealproportionshavenotbeenestablishedforfancyshapes.Manyvariationsinfancyshapesaresimilartothoseinroundbrilliants,butsomeareunique.Theseincludethedark"bow-tie"thatcanbeseenatthemidsectionofsomefancyshapebrilliants,excesspavilionbulgeinemeraldcuts,extremelength-to-widthratios,andunattractivegirdleoutlines.

symmetry• Themainconcernwithcutsymmetryishowpreciselyoppositesidesofthediamondmatch.

Anotherconsiderationistheexactnessoffacetshapeandplacement.• Fordiamondcutsymmetry,theidealisamirror-likebalancefromonesideofthediamondtothe

other,witheachfacetperfectlyshapedandpositioned.Thiscreatesanevendisplayofbrilliance,dispersion,andscintillation.

• Achievingidealsymmetryrequiresgreatattentiontodetail.Thisaddstothetimeandlaborofcutting.

• Mostdiamondshaveminorsymmetryirregularitiesthathavelittleornoeffectonappearance.Majorsymmetryproblems–suchasanobviouslyout-of-roundgirdle–hurtadiamond’sopticalperformanceandvisualappeal.Asaresult,theydiminishvalue,too.Likeextremeproportionvariations,theyrepresentweightandtimesavedattheexpenseofbeauty.

13 The Diamond Course Compendium

CUT QUaLiTY

Girdle

Crown Height

Pavilion Depth

Girdle Thickness

Girdle DiameterTable Size

KEY PROPORTIONS

CUT QUaLiTY

The Diamond Course Compendium 14

Polish• Becauseoftheirsuperiorhardness,diamondscan

takeandkeepapolishthatfarsurpassesothergems.Foradiamondtodisplayitsbestbrilliance,dispersion,andscintillation,thehighestdegreeofpolishisessential.

• Polishqualityanditseffectonvaluereflecttheskill,care,andtimetakeninthecuttingprocess.Almostalldiamondshaveminorpolishblemishes,butpoorpolishcanmakeadiamondlookdullandfuzzyregardlessofthequalityofitsproportionsandsymmetry.

• Theveryrareunionofidealproportions,idealsymmetry,andidealpolishcreatesthetrueidealcutdiamond.

hearts and arrows• "Heartsandarrows"isareflectionpatternthatcanbeseeninsomeroundbrilliantcutswiththeaid

ofaspecialopticaldevice.Thepatternactuallyhastwocomponents.Theheartscanbeseenwhenthediamondisviewedtable-down,whilethearrowscanbeseentable-up.

• Theheartsandarrowsappearonlyifthediamond’sproportionsandsymmetryarerelativelygood.Notallwellcutdiamondsshowthepattern,however.Indiamondsoflowcutquality,theheartsbecomedistorted,andthearrowsdisintegrateintoajumbledmosaic.

evaluating Cut Quality • Toanalyzeproportions,manydiamondgradersuseacombinationoftechniques.Theyvisually

estimatesomeproportions,andcalculateothersfromcarefulmeasurements.Symmetryandpolisharejudgedmuchlikeclarity.

• Instrumentscannowevaluatesomeaspectsofcut,butnoinstrumentcanyetprovidetheentirepictureofcutquality.Ahumanexpertmuststilldeterminethat.

• Severalcutgradingsystemscurrentlyexist.TwoofthemostwidelyusedweredevelopedbytheAmericanGemSociety(AGS)andtheGemologicalInstituteofAmerica(GIA).TheAGScutgradescaleconsistsofelevengrades–0to10,with0beingbest.GIAgradescutqualityasexcellent,verygood,good,fair,orpoor.

15 The Diamond Course Compendium

Cut Quality and Value • Manyexpertsregardidealcutsasthehighpointofhumanartandnaturalbeautyindiamonds.

Theirvalueisadirectresultofgreaterweightsacrificeandskilledlabor.• Formanycustomers,adiamondwithgood(thoughnotideal)cutqualityoffersabalanceofbeauty

andvalue.• Manycutqualityvariationsarecomparabletomicroscopicclaritycharacteristicsorfainttintsof

color.Proportionsnormallyvarywithinsmallpercentages.Mostsymmetryandpolishfeaturesarevisibleonlywithmagnificationorspecialinstruments.

• Poorcutqualityisoftenthehiddenfactorin"discount"diamonds.Twodiamondsthatareequalincaratweight,clarity,andcolorcandiffersubstantiallyinbeautyandvaluebecauseofdifferencesincutquality.

CUT QUaLiTY

The Diamond Course Compendium 16

TreaTMenTs, sYnTheTiCs, anD siMULanTs

TREATMENTS,SYNTHETICS,

AND SIMULANTS Basic Definitions• Treateddiamond–Adiamondthatformednaturallybutunderwentalaboratoryprocesstoimprove

itsappearance.• Syntheticdiamond-Adiamondthatwasmadeinalaboratoryormanufacturingfacility.Ithas

essentiallythesamecomposition,structure,andpropertiesasanaturaldiamond,butwasproducedbytechnologicalmeans.

• Diamondsimulant–Adiamondlook-alike.Diamondsimulantsarenotdiamonds.Theyonlyresemblediamonds.

Diamond Treatments • Atreateddiamondisadiamondthatformednaturally,butunderwentalaboratoryprocessto

improveitsappearance.• Commercialdiamondtreatmentscanaffectclarityorcolor.Therearefourmainmethods–laser

drilling;fracturefilling;irradiation;andhigh-pressure,high-temperature(HPHT).—LaserDrilling–Laserdrillinglightensdarkinclusions.Toaccomplishthis,ahigh-powerlaser

usuallyburnsatinychannelintothediamondtoreachtheinclusion;thenacidisinjectedtobleachit.Thetreatmentleavesamicroscopicdrillhole,whichbecomesanaddedinclusion,butthediamond’soverallappearanceisimproved.

Photo courtesy Russian Diamond Company.

—FractureFilling–Thistreatmentmakesinternalbreakslessvisible.Ifabreakreachesthediamond’ssurface,itcanbefilledwithaglass-likematerial.Asaresult,thebreakmayseemtoalmostdisappear.Occasionally,alaserchannelisdrilledtoanenclosedbreakandthefillerisinjected.Thisconcealsboththebreakandthedrillhole.

—Irradiation–Irradiationmostoftencreatesfancycolorinlightyelloworbrowndiamonds.Itcanalsodeepenorintensifyothercolors.Thereareseveraltechniques,andtheyareoftencombinedwithcontrolledheating.Earlyirradiationtreatmentssometimesmadediamondsdangerouslyradioactive,butcurrentmethodsleavenoresidualeffectsandcreatenohealthrisks.

—High-pressure,high-temperature(HPHT)–Thistreatmentaltersadiamond’scoloratthemolecularlevel.ThemethodoriginallydevelopedbytheGeneralElectricCompanyremovessomeorallcolorfromcertaintypesoflightbrowndiamonds.Otherversionsofthetreatmentcancolorsomediamondspink,blue,yellow,green,ororange.HPHTtreatmentorhightemperaturealoneisalsousedtocolordiamondsblack.

• Withtheinstrumentsandtestsavailableinmanyjewelrystores,aqualifiedgemologistcanidentifylaserdrillingandfracturefilling.ManyirradiateddiamondsandmostHPHTtreateddiamondscannotbepositivelyidentifiedwithstandardtests,butlaboratorygemologistsworkingwithadvancedinstrumentscanusuallymakethedetermination.Tomakedetectioneasier,manyHPHTtreateddiamondsarelaserinscribedwithamicroscopiccodeorlogo.

• Commercialdiamondtreatmentsareconsideredethicalaslongastheyaredisclosedtothebuyer.FTCguidelinesrequiredisclosureofalldiamondtreatments.

Permanence and special Care:LaserdrillingandHPHTarepermanentandrequirenospecialcare.

Irradiationispermanentunderconditionsofnormalwear,butveryhighheatmayaffectit.Thiscouldcomefromajewelers’torchduringrepairwork.Anotherpossiblesourceisahousefire.

Fracturefillingcanbedamagedbyhighheatandcertaincleaningmethods.

Treatment’s effect on Value:Theexpenseofthetreatmentprocessisaddedtotheoriginalcostofthediamond.Treateddiamondsareworthmorethantheywerebeforetreatment,butlessthanuntreateddiamondsofcomparableappearance.

17 The Diamond Course Compendium

TreaTMenTs, sYnTheTiCs, anD siMULanTs

Photos courtesy Gary Roskin.

Laser-drilled diamond.

Fracture-filled diamond.

The Diamond Course Compendium 18

TreaTMenTs, sYnTheTiCs, anD siMULanTs

synthetic Diamonds • Asyntheticdiamondisadiamondthatwasmadeinalaboratory.Ithasessentiallythesame

composition,structure,andpropertiesasanaturaldiamond,butwasproducedbytechnologicalmeans.Othertermswiththesamemeaningarelaboratory-createddiamondandlaboratory-growndiamond.

• TheSyntheticDiamondTimeline:1950s Thefirstsyntheticdiamondswereproduced.Thesewerenotgemquality,butthey

representedamajorbreakthrough.1970 Aroundthisyear,gemqualitydiamondswerefirstsynthesized.Theprocesswasextremely

expensive,however.Duringthenextdecadeandahalf,limitedquantitiesweremadeforscientificandtechnicalpurposes.

1985 Commercialproductionofgemqualitysyntheticdiamondsbegan.Atfirst,thesewerealsousedinscience,technology,andindustry.

1990sSyntheticdiamondsbegantoappearinthejewelrymarket.2000sThesupplyofsyntheticdiamondshasincreasedsteadilyandhasalsodiversified,with

expandedcolorchoices,largercaratweights,andimprovedquality.Quantitiesarestillverylimitedcomparedtotheoutputofnaturaldiamonds,butthesupplyiscertaintogrowinthefuture.

• Mostsyntheticgemdiamondsproducedtodayarefancycolors.Yellowsandbrownsaremostabundant.Othercolorsincludepink,blue,orange,andred.Nearcolorlesssyntheticgemdiamondsarestillrelativelyrare,buttheiravailabilityisincreasing.

• Industryexpertsareconvincedthatsyntheticdiamondswillfindamarketnicheoftheirown.Thishasalreadyoccurredwithsyntheticversionsofemerald,ruby,sapphire,andothergems.

• Mostsyntheticdiamondscanbeidentifiedwithstandardtests.Tradelaboratoriescanuseadvancedteststoidentifyallsyntheticdiamonds.Tomakedetectioneasier,manysyntheticdiamondsarelaserinscribedwithamicroscopiccodeorlogo.

Diamond simulants • Adiamondsimulantisadiamondlook-alike.Diamondsimulantsarenotdiamonds.Theyonly

resemblediamonds.Othertermsthatmeanthesamethingareimitationandsimulateddiamond.• Diamondsimulantshavealonghistory.Colorlesssapphireandquartzarenaturalgemstonesthat

havebeenusedasdiamondsimulantsforcenturies.Anothernaturalsimulantiscolorlesszircon.• Theoldestmanmadesimulantisglass.Ithasimitateddiamondsincethe1500s.Colorlesssynthetic

sapphireandsyntheticspinelappearedintheearly1900s,andtherewereanumberofartificialimitationsthroughoutthe20thcentury.Glass,syntheticsapphire,andsyntheticspinelaremostimportantintermsofvolume.

19 The Diamond Course Compendium

• Formanyyears,syntheticcubiczirconia(CZ)wasregardedasthebestdiamondsimulant.CZisnowavailableinmanycolors,andisoftenmarketedasalab-createdgeminitsownright.

• Themostrecentgemmaterialthatcouldbeconsideredadiamondsimulantissyntheticmoissanite.Thisenteredthemarketinthe1990s.Expertshavedescribeditasclosertodiamondinappearancethananyothergem.However,moissaniteisprimarilymarketedasauniquelab-createdgem–notasadiamondsimulant.

• Alldiamondsimulantscanbeidentifiedwithstandardinstrumentsandtests.

TreaTMenTs, sYnTheTiCs, anD siMULanTs

synthetic moissanite.

Photo courtesy Richard Drucker - The Guide’s Gem Market News.

Cubic Zirconia

Photo courtesy Golay Buchel.

PrOPerTies anD fOrMaTiOns

The Diamond Course Compendium 20

PROPERTIESAND

FORMATIONDiamond formation • Diamondsaremadeofcarbonthatcrystallizedlongago,deepinsidetheEarth,underconditionsof

immenseheatandpressure.• Theoldestdiamondsformedabout3.3billionyearsago,andtheyoungestarealmost1billion

yearsold.(Theageoftheearthisabout4.54billionyears.)• Diamondsformedattemperaturesthatrangedfromabout1,700°to2,400°Fahrenheit,and

pressuresbetween650,000and870,000poundspersquareinch.Super-strongmechanicalpressesnowrecreatesimilarconditionstoproducesyntheticdiamondsandhigh-pressure,high-temperature(HPHT)treatments.

• Mostdiamondscrystallized90to120milesbeneaththeEarth’ssurface,andsomeoriginatedatevengreaterdepths.

• Underlaboratoryconditions,ittakesadayortwotomanufacturea1-caratsyntheticdiamond.Manynaturaldiamondscouldhavegrownthatquickly,butlarge,highqualitycrystalsmayhavetakencenturiestoform.

Photo courtesy De Beers Group.

21 The Diamond Course Compendium

Diamond Crystals • Diamondiscomposedofalmostpurecarbon,andthearrangementofcarbonatomswithinthe

crystalisalmostperfectlysymmetrical.• Gemqualitydiamondsaretypically99.95%carbon,andtheycanbemorethan99.99%pure.This

makesdiamondoneofthepurestofallmaterialsfoundinNature.• Diamondisalsotheonlygemcomposedofjustoneelement.Allothergemsarechemical

combinations.• Carbonatomsbuilddiamondcrystalsbysharingelectrons.Each

carbonatombondswithfourneighborstoformatetrahedron–thesimplestandstrongestofallthree-dimensionalconfigurations.Thedistancebetweeneachpairofbondedcarbonatomsisonly600millionthsofaninch.

• Thearrangementofcarbonatomsingemqualitydiamondcrystalsisalmostperfectlysymmetricalineverydirection.Sometimesthisstructureproducescrystalsofperfectgeometry.Moreoftentheexternalshapesarenotperfect,andmanycrystalsaredistortedorbroken.Despitetheexternalshape,however,theinternalorderisalwaysthere.Itexistsattheatomiclevel.

Diamond Properties • Thecombinationofchemistryandstructureistheinnersourceofdiamond’sbeautyandother

properties.Thesepropertiesincludehardness,toughness,density,refractiveindex,dispersion,andfluorescence.

• Hardness–Resistancetoscratching.Diamondisthehardestknownmaterial.TheMohsHardnessScalerateshardnessfrom1to10,basedonwhetheronematerialscratchesanother.OntheMohsScale,diamondis10,corundum(rubyandsapphire)is9,andtopazis8.(Moreprecisetestsshowthatdiamondis140timesharderthanrubyorsapphire,and300timesharderthantopaz.)Superiorhardnessisthereasondiamondcantakeandkeepapolishthatisfarbetterthananyothergemstone’s.

• Toughness–Resistancetobreaking.Toughnessisratedasexceptional,excellent,good,fair,orpoor.Diamond’soveralltoughnessisgood.Itwouldbeexcellentifnotforthepropertyknownascleavage,whichisthepotentialtobreakincertaincrystaldirections.

Diamond’shardnessandtoughnessmakeitoneofthemostdurableandwearableofallgems.Evendiamondsrequirepropercare,however.PleaseseethesectiononDurabilityandCareforadditionalinformation.

PrOPerTies anD fOrMaTiOns

Diamond octahedron.

Diamond dodecahedron.

The Diamond Course Compendium 22

• Density–Therelationshipbetweensizeandweight.Onewayofexpressingdensityisspecificgravity(SG),whichisanumberthatindicatestheweightofamaterialcomparedtotheweightofanequalvolumeofwater.Gemqualitydiamond’sSGistypicallyverycloseto3.52.Thisisoneofthepropertiesthatcanbeusedtoseparateunsetdiamondsfromsimulants.

• Refraction–Theslowingandbendingoflightinatransparentmaterial.Thispropertyismeasuredbytherefractiveindex(RI),whichcomparesthespeedoflightinairtoitsspeedinthematerial.Diamond’sRIis2.417.Thismeansthatlightslowstoabout40%ofitsnormalspeedinsideadiamond.(Whenlightleavesthediamond,itburstsbacktoitsoriginalspeed.)HighRIandhardnesscontributetodiamond’sbrillianceandscintillation.

• Dispersion–Thisistheseparatingofwhitelightintospectralcolors.Itiscausedbydifferentcolorsoflightbeingrefracteddifferently.Diamond’sdispersionis0.044.Thisishigherthanmostothernaturalgems,butitissurpassedbysimulantssuchasCZandsyntheticmoissanite.

• Fluorescence–Theglowsomediamondsemitinlightthatcontainsultraviolet(UV).Themostcommonfluorescencecolorisblue.Othersarewhite,yellow,andorange.

formation and the 4Cs • DiamondswereborninthewildestofallenvironmentsonEarth.Amidthemassiveandviolent

forcesoftheplanet’sinterior,manythingscouldhavegonewrong.Itisalmostamiraclethatdiamondsexistatall.

• Many(perhapsmost)diamondsperishedbeforetheyreachedthelightofday.Ofthosethatsurvived,onlyafractionaregemquality.

• Evenminorvariationsincomposition,structure,orthegrowthenvironmentsometimeshadmajorimpactsonthefactorsthataffectadiamond’svalue:—CaratWeight–Everydiamondcrystal’ssizewaslimitedbyhowlongtherightgrowing

conditionsexisted.Onlyonegemqualitycrystalinathousandgrewlargeenoughtoyieldahighqualityfinisheddiamondweighingonecaratormore.

—Clarity–Highclaritydiamondsformedunderveryfavorableconditions.Astheyweregrowing,diamondsoftenengulfedsmallercrystalsofotherminerals(orotherdiamonds)thatbecameinclusions.Theimmensestressesinvolvedinformationfrequentlycausedinternalbreaks.

—Color–Colorlessdiamondsmusthaveformedunderconditionsthatwereclosetoideal.Minute

PrOPerTies anD fOrMaTiOns

Diamond cube - rare in gem quality diamond.

23 The Diamond Course Compendium

amountsofnitrogentintedmostdiamondsvariousshadesofyellow.Morerarely,tracesofboronproducedbluediamonds.Distortionsinthecrystalstructureoftenresultedinbrowntints.Theyalsocreatedpinks,reds,andpurples.Otherdiamondcolorscamefromcombinationsoftraceelementsandstructuralirregularities.

—Cut–Diamond’scrystalstructuredictateshowitcanbecut.Thecrystalformorsignificantclaritycharacteristicsoftendeterminetheshapethecutterchooses.

• Fromthestandpointofformation,the4CsaresimplyoutcomesoftheastonishingprocessthroughwhichNatureshapedeachdiamond’spotentialforbeautyandvalue.

PrOPerTies anD fOrMaTiOns

Diamond macle.

The Diamond Course Compendium 24

DEPOSITS,SOURCES,

AND MININGDeposits and Mining • DiamondsweredeliveredtoEarth’ssurfacebyvolcaniceruptions.Themoltenrock(ormagma)

thatfueledtheeruptionsoriginatedatleast90to120milesdown,andpossiblydeeper.Thisisagreaterdepththananyotherkindofvolcanicactivityonourplanet.

• Therearetwomaintypesofdiamonddeposits–primaryandsecondary.Primarydepositsareplaceswherediamondswerefirstbroughttothesurface.Secondarydepositsareplaceswherediamondswerecarriedbyerosion.

• Primarydepositswerecreatedbyeruptionsofdiamond-bearingmagmas.Themostimportantareknownaspipes,andtheyarethegeologicremainsofrelativelylargeeruptions.Inmostpartsoftheworld,thefocusofdiamondexplorationandminingisonpipes,becausetheyhaverelativelylongproducinglivesandtheyaresuitedforlarge-scalemining.

• Thetimefrombeginningofexplorationtothestart-upofamajorpipemineisoftenmorethanadecade,andtheinvestmentcaneasilytophalfabilliondollarsbeforethefirstfullshipmentofdiamondsgoestomarket.

DePOsiTs, sOUrCes anD Mining

The “Big Hole” was once the thriving Kimberly Mine.

25 The Diamond Course Compendium

DePOsiTs, sOUrCes anD Mining

• Diamondpipesvarygreatlyinsize.Oneoftheworld’slargest–theOrapapipeinBotswana–coveredabout260acresandthemainminingsectionwasmorethanamiledeep.Theaveragesizepipeisaroundthirtyacres.Mostdiamondpipesarecarrot-shapedconesthatgraduallytaper.Asoperationsgodeeper,thepipenarrowsandyielddecreasesuntilthemineisnolongerprofitable.Theaveragelifespanofadiamondpipemineisaboutthirtyyears.

• Onereasondiamondsarecostlyisthetremendouslaborrequiredtoobtainrelativelysmallquantitiesoftheendproduct.Foreachpointoffinisheddiamondweight,workersandmachinesexcavatemorethan1,000poundsoforeandrock.

Production and sources • Worldproductionisnowaround130millioncarats

peryear,withavalueofabout$14billionattheminelevel.Alittlemorethanhalfthetotalweightisofficiallyclassifiedasgemquality,butthatrepresentsmorethan90%ofthevalue.Inadditiontofinediamonds,itincludes"near-andcheap-gemqualities."Therestisindustrial,usedmainlytomakeabrasivesandcuttingtoolsformining,construction,andmanufacturing.

• Historically,IndiaandBrazilaretheoldestsourcesofdiamonds.MininginIndiamayhavebegunasearlyas500BC,andformorethan2,000years,Indiawastheworld’sonlydiamondproducer.Annualoutputwasneverhighbymodernstandards,butmanyfamousdiamondscamefromIndia.DiamondswerefoundinBrazilduringtheearly1700s,andthatcountrybecamethemaindiamondsourceforthenext150years.Today,diamondexplorationandminingcontinueinbothcountries,butmostactivityisinotherpartsoftheworld.

• Diamondsarecurrentlybeingminedinmorethan20countries.MostofthesearelocatedinAfrica.Addedtogether,Africanproducerssupplymorethanhalftheworld’sroughdiamonds,measuredbyweightorvalue.TherearealsoimportantproducersoutsideAfrica.Onanindividualbasis,thetopthreediamondproducingcountriesbyvalueareBotswana,Russia,andCanada.ThetopthreebyweightareRussia,Botswana,andtheDemocraticRepublicoftheCongo.

• Overthenextdecadeorso,anumberofthediamonddepositsnowbeingminedwillbecomedepleted.Althoughminingmethodsareincreasinginefficiency,prospectsfornewdepositsandminesareuncertain.Asaresult,worlddiamondproductionmayholdsteady,orperhapsdecline.

• Byworldstandards,theUnitedStateshasneverbeenasignificantdiamondproducer,butisolateddiamondshavebeenfoundinalmosteverystate.Therearediamond-bearingformationsinArkansas,Colorado,Michigan,andWyoming.InArkansasandColorado,thedepositshavebeendevelopedtoalimitedextent.

Photo courtesy Argyle.

The Diamond Course Compendium 26

DePOsiTs, sOUrCes anD Mining

The Kimberley Process • TheKimberleyProcessisaresponsetotheconflictdiamondsissue,whichemergedinthe1990s.

Atthattime,somediamondsfromtheAfricancountriesofAngola,DemocraticRepublicoftheCongo,andSierraLeonewerebeingminedandsoldtofinancecivilwars.

• AttheheightoftheAfricancivilwars,conflictdiamondsrepresentedonlyatinyfractionoftheworld’stotaloutput.Thosewarshavenowdiminishedorended,andtheflowofconflictdiamondshasdroppedwiththem.

• Aglobalcoalitionhastakenstepstoendtheconflictdiamondsproblem,andmakesurethatitcannothappenagain.ThestartingpointforthiseffortistheKimberleyProcessCertificationScheme.Itsaimistopreventconflictdiamondsfromenteringmarketsupplychannels.Therearetwomainprovisionsforaccomplishingthisgoal:—AcountrythatparticipatesintheKimberleyProcessmayonlyimportroughdiamondsfrom,or

exportthemto,otherparticipatingcountries.

—Whenashipmentofroughdiamondsgoesfromoneparticipatingcountrytoanother,itmustbeinatamper-proofcontainer.Itmustalsohaveagovernment-issuedKimberleyProcessCertificate.

• TheKimberleyProcesswasimplementedin2003,anditisnowenforcedbymorethan80countries.Industryorganizationsandfirmsateverylevelhavealsoadoptedasystemofwarrantiesthatextendsallthewaytotheretailshowcase.

• Thevastmajorityofdiamondsflowthroughlegitimatechannels.Theyarevitaltotheeconomiesofnationsandtheincomesofpeoplearoundtheworld.Anydiamondthatsupportswarorterrorisonetoomany,butwithallofthesafeguardsthatarenowinplace,thechanceofaconflictdiamondreachingajewelrystoreintheUSisalmostzero.

The Diamond Course Compendium 27

The DiaMOnD inDUsTrY

THE DIAMONDINDUSTRY

De Beers and the DTC • HugediamonddepositswerediscoveredinSouthAfricaaround1870.Inthefollowingyears,world

diamondproductionincreasedmorethan1,000%.Thiseventuallymadediamondsmoreavailabletoconsumers,buttheshort-termeffectswereoversupplyandfallingpricesthatthreatenedtoruinthediamondindustry.

• CecilRhodes(1853-1902)wantedtobalancesupplyanddemand,andhebelievedthatcontrollingsupplywasthewaytodoit.RhodesandhisbusinesspartnersfoundedDeBeersConsolidatedMinesin1888,andby1900thecompanyowned90%ofworlddiamondproduction.AfterRhodes’death,DeBeerssufferedalongperiodofuncertainty.

• EarnestOppenheimer(1880-1957)becamechairmanofDeBeersin1929,andheadedthecompanyforthenext28years.Inthe1930s,Oppenheimercreatedastructuretocontroltheflowofroughdiamondstothemarket.Around1940,DeBeersbeganworkingwithtopadvertisingagenciestomakediamondspartofmodernromance.Basedonthetheme"ADiamondIsForever,"thiseffortdevelopedtoday’sconsumermarketfordiamonds.

• EarnestOppenheimer’ssuccessorsincludedhissonandgrandson.HarryOppenheimerwaschairmanofDeBeersfrom1957-1984,andNicholasOppenheimerheldthatpositionfrom1997to2011.

• TodayDeBeersistheworld’slargestdiamond-producingentity.ItownsmostofSouthAfrica’sdiamondmines,andhasonemineinCanadathat’sbeingdeveloped.ItalsoownsandoperatesminesinpartnershipwiththegovernmentsofBotswanaandNamibia.Togethertheseassetsproduceabout30%ofallroughdiamondsbyweightandaround35%byvalue.

• In2000,DeBeersturnedoverallitssalesandmarketingactivitiestotheDiamondTradingCompany(DTC),whichhaspositioneditselfastheSupplierofChoiceinaworldwidedistributionchannel.

Photo courtesy BHP.

28 The Diamond Course Compendium

Diamond suppliers • Formostofthe20thcenturyDeBeershadnearlytotalcontroloftheworld’ssupplyofrough

diamonds.Sincethemid-1990s,othercompanieshaveemergedinthissector.Todaytherearefiveleadingsuppliersofroughdiamonds:– DiamondTradingCompany–TheDTCmarketsdiamondsfromminesownedpartlyor

completelybyDeBeers.Italsobuysandsellsdiamondsfromotherproducers.TheDTCiscurrentlythetopdiamondproducingcompanymeasuredbyvalue.

– ALROSA(AlmazyRossi-Sakha)–Russia’sstate-rundiamondcompany.ItmarketsroughdiamondsminedintheRussianFederation.ItisalsopartownerofthelargestdiamondmineinAngola.ALROSAisthetopdiamondproducingcompanybyvolume.

– RioTinto–Agiantmetalsandmineralsminingcompany,withoperationsin40countries.RioTintoownsandoperatestheArgylemineinAustralia,andhasa60%shareofCanada’sDiavikmine.

– DominionDiamond–Thiscompanyowns80%ofCanada’sEkatimine,andisthatmine’soperator.Italsoowns40%ofDiavik.

– SODIAM(SociedadedeDiamantesdeAngola)–Managesdevelopment,mining,andmarketingofdiamondsproducedbyAngola.(Inrecentdecades,Angolahasconsistentlyrankedamongthetop10diamondproducingnations.)

Trading and Cutting Centers Throughsuppliersandothersources,roughdiamondsreachtradingandcuttingcentersaroundtheworld.ThemostimportantofthesearelocatedinBelgium,theUnitedStates,Israel,Russia,India,China,andtheUnitedArabEmirates..

—Belgium–ThecityofAntwerphasbeenacenterofdiamondtradingandcuttingsincethe1400s.Today,ithasthelargestconcentrationofcompaniesintheindustry.Theseincluderoughproducersandwholesalers,cuttingfirms,andpolisheddiamondwholesalers.Antwerp’scuttershavetheabilitytodealwithlargeandvaluablerough,andmanyfamousdiamondshavebeencuthere.Currently,about80%ofallroughdiamondsand50%ofallpolisheddiamondspassthroughthisindustrycenter.

– UnitedStates–DiamondtradingandcuttinggooninanumberofUScities,withNewYorkasthecenterofmostactivity.Cuttershavebeenworkingheresincethe1800s.Mostnowspecializeinlarge,highqualitydiamondscuttohighstandards.NewYorkisalsothemainentrypointanddistributioncenterfortheentireUS.About40%ofalltheworld’sdiamonds,measuredbyvalue,flowthroughNewYork’sDiamondDistrictenroutetoAmericanconsumers.

The DiaMOnD inDUsTrY

Photo courtesy JCK.

The Diamond Course Compendium 29

– Israel–Thiscountrybecameamajorcuttingcenterinthe1950s,andwasintheforefrontofthatsectoruntilrecently.Israel’scuttingfirmsproducemanyfinediamondsinlargerweightcategories–2caratsandover.Israelalsoleadstheworldinthedevelopmentanduseofnewcuttingtechnology.Inrecentyears,ithasbecomeamajortradingcenteraswell.

– Russia–Russia’scuttingindustrybeganinthe1960s.Allitsfactorieswereonceownedbythegovernment,andsomestillare.Russiaisnotedforqualitycuttinginpopularweightcategories.Inthepast,Russiancuttersworkedmainlywithroughthatwasminedinsidethecountry.Nowthey’reimportingfromothersourcestoo.

– India–Cuttingalsostartedhereinthe1960s.Withlowlaborcosts,Indiancuttersfirstworkedonsmall,low-qualitydiamonds.Indiaisstillaleaderinthatcategory,butit’sprocessinglarger,higherqualitydiamondsaswell.TodayIndiaistheworld’slargestcuttingcenter.Accordingtoreportsbyitsgovernmentandnationaltradeorganization,Indiacutsmorethan50%oftheworld’sdiamondsbyvalue,about80%byweight,andover90%byvolume(ornumberofindividualdiamonds).

– China–Inthe1980s,theChinesegovernmentmadeabigpushtostartadiamondcuttingindustry.AlthoughChinahassomeoftheworld’smostinexpensivelabor,itsworkersareskilledandthey’rebeingtrainedbyexpertsfromothercountries.LeadingfirmsfromBelgiumandIsraelhavetransferredtheirpolishingoperationsthere.Asaresult,Chinaisnowtheworld’ssecondlargestdiamondcuttingcenter.

– UnitedArabEmirates–Since2004,thecityofDubaihastakenaplaceamongtheworld’stopdiamondtradingcenters.TheUAEgovernmentactivelysupportsdevelopmentofthediamondtradeandDubainowhostsmorethan500regionalandinternationalcompanies.Thesearemostlyfocusedontradingroughandpolisheddiamonds,butsomeareexpandingintootherareas,includingcoloredgemstones,diamondcutting,andjewelrymanufacturing.

Trade Laboratories • Tradelaboratoriessupplythejewelryindustrywithexperttechnicalservicesintheareasofproduct

testingandgrading.• Inthe1950s,GIA’stradelaboratorybeganissuingdiamondgradingreports.Theseverifiedthe4Cs

forretailjewelersandotherprofessionals.Sincethen,thediamondindustryhascometorelyongradingreports,andthenumberoflabsissuingthemhasgrown.

• Diamondgradingisthemainserviceformostlabs,butsomealsoidentifytreatmentsandlaser-inscribediamonds.Otherstestcoloredgemsandjewelrymetals.

• Laboratorydiamondgradingproceduresaredesignedtomaximizeaccuracyandconsistency.Inmostlabs,twoormoretrainedgradersexaminethediamondindependently.Thentheresultsarecompared,discrepanciesarereconciled,andthefinalreportisissued.

The DiaMOnD inDUsTrY

The Diamond Course Compendium 30

DIAMONDCUTTING

• Cuttingisakeystepinadiamond’sjourneyfromtheminetothejeweler’sshowcase.Whentheycomefromthemine,mostdiamondslooklikefrostedpebbles.Whentheyleavethecutter’swheel,theyareradiantgems.

• AlthoughdiamondsarethehardestmaterialsonEarth,slighthardnessdifferencesexistwithineverydiamond.Thedifferencesarelinkedtothegeometryofthecrystalstructure.Asaresult,theharderdirectionsofsomediamondscanbeusedtocutthesofterdirectionsofothers.

• ModerndiamondcuttingbegantoevolveinItalyduringthe1300s.Before1700,mostofthebasicmethodshadbeendeveloped.Exceptforthespeedandprecisionmadepossiblebytechnology,manymethodshavechangedlittlesincethen.

• Acutter’sobjectiveistoproducemaximumvaluefromeveryroughdiamondcrystal.Thatmeanstransformingthenaturalfeaturesofthecrystalintothebestcombinationof4Csinthefinishedgem.Toaccomplishthis,anumberofvariablesmustbeconsideredandbalancedintheplanningstage.

• Beforeshapingandpolishing,manydiamondcrystalsmustbedivided.Therearetwowaystodothis–cleavingandsawing.—Cleavingusesforcetosplitthediamondinaweakcrystaldirection.Thisisanoldtechnique.It

isnowusedmainlytodividelargediamondsintopiecesthatcanbeshapedmoreeasily.

—Sawingusesametalbladeanddiamondgrit,orelseintenseheatfromalaser,tocutthroughthecrystal.Thisresultsingreatercontrolofthefinalshapeandweight.

DiaMOnD CUTTing

31 The Diamond Course Compendium

• Thenextcuttingstepisshapingthediamond’sgirdleoutline.Withstraight-sidedshapes,thisisdonebygrinding.Roundandfancyshapebrilliantsrequireaspecialtechniqueknownasbruting.Onewaytodothisistomounttwodiamondcrystalsinaspeciallydesignedmachine,andtospinthemsotheirouteredgesrubagainsteachother.Anotheroptiontodayislaserbruting.

• Thediamondisfacetedandpolishedonascaife,whichisanelectricallydrivencast-irondiskabout12to16inchesindiameter.Itrotatesatabout2,500to5,000RPM.Thescaifeiscoatedwithdiamondgrit,whichgrindsawaythecrystalthatisbeingcut.

• Inrecentyears,manydiamondcuttingfirmshavebegunusingautomatedpolishingmachines.Theseoftencutdiamondswithfinishedweightsfrom5pointsto1carat.Manyarecomputerized,andmostpolisheverythingexceptthetableandthefacetsthatsurroundit.Thesearestillpolishedmanually.

DiaMOnD CUTTing

The Diamond Course Compendium 32

DIAMONDMAGIC ANDROMANCE

nature’s inspirations • Diamond’snaturalcharacteristicshaveinspiredsomeoftheoldestandstrongestelementsofits

magicandromance.• Diamondisthehardestknownmaterial,anditisalsoverytough.Reflectingtheseproperties,the

EnglishworddiamondcomesfromtheGreek"adamas",meaningunconquerable.Forcenturies,mostpeoplemistakenlythoughtdiamondsareindestructible.Byaprocessofassociationtheycametobelievethatdiamondsblesstheirownerswithstrength,courage,success,andenduringlove.

• Toancientphilosophers,well-formeddiamondcrystalsseemedtoembodytheorderoftheuniverse,symbolizingthehighestmental,emotional,andspiritualbalance.Today,cutstylessuchastheroundbrilliantandprincesscutstillreflectthismeaning.

• Diamond’sclarityandcolorlessnesshavelongbeenequatedwithpeaceofmindandpurityofheart.Itsbrillianceandfirehavebeenseenastokensofenlightenmentandlife-sustainingenergy.

DiaMOnD MagiC anD rOManCe

33 The Diamond Course Compendium

Cultural Contributions • Tothesymbolsandmeaningsderivedfromdiamond’snaturalcharacteristics,culturesthroughout

historyhavecontributedmanyothers.• Diamondhasbeenabirthstoneforthousandsofyears.InancientIndia,diamondwasassignedto

thosebornunderthesignsnowknownasTaurusandLibra.ModernWesternzodiacchartslistdiamondasaluckygemforTaurusandAries.Sincethe1800s,diamondhasbeendesignatedastheAprilbirthstoneinEuropeandAmerica.Diamondisalsoconsideredthegemforwinter,Saturday,and12noon.

• Accordingtosomeoldlegends,diamondsarebornfromheavenlyrainorlightning.Otherssaytheyaresplintersofbrokenstars,possessingtheabilitytobestowwealth,friends,eternalyouth,andhappymarriage.TheRomansbelievedCupid’sarrowsweretippedwithdiamonds.Othermagicalattributesincludedbringingsweetdreams,wardingoffevilspirits,andmakingthewearerinvisible.

• Manycultureshavebelievedthatadiamond’smagicalpowersandvirtuesareenhancedwhenitisgivenasagift.

Diamond Occasions • DiamondjewelryfirstappearedinEuropeduringthe

RomanEmpire,butitwasprobablyworninIndia(theworld’soldestsourceofdiamonds)longbeforethen.

• InmodernAmericanculture,themostimportantdiamondoccasionisengagement.Today,eightoutoftenfirst-timebridesintheUSreceiveadiamondengagementring.Theaveragesizeofthediamondisabout1/2to1carat.

• Thecustomofgivingengagement(orbetrothal)ringsbeganinRomantimes.PlacingtheringonthefourthfingerofthelefthandalsomayhavebegunwiththeRomans,whobelievedthereisadirectconnectionbetweenthatfingerandtheheart.

• Diamondshavebeenassociatedwithengagementformorethan500years.In1477,ArchdukeMaximilianofAustriagaveadiamondbetrothalringtoMaryofBurgundy.Thisisthefirstdiamondengagementringofficiallyrecordedbyhistory.Forcenturiesafterward,diamondengagementringswerepartofroyalcourtship.TheybecameanAmericantraditioninthe1900s.

• Apartfromengagementsandweddings,anniversariesarethemostfrequentoccasionsforgivingandreceivingdiamondjewelry.IntheUS,the10th,60th,and75thanniversariesaretraditionallyassociatedwithdiamonds.Today,the25thanniversaryisalsoanimportantdiamondoccasion.However,anyanniversarycanbeperfectforexpressinglovewithagiftofdiamonds.

DiaMOnD MagiC anD rOManCe

The Diamond Course Compendium 34

Diamond Celebrities • Throughoutmostofhistory,diamondscouldonlybewornbyroyalty.Thisgavediamondsanaura

ofregalsplendorthatstilllingers.Inmoderntimes,popularentertainmentfiguresandcelebritieshavecontinuedtoenhancetheglamourofdiamonds.

• Inthe1953musical-comedyGentlemen Prefer Blondes,MarilynMonroeworethe24-caratMoonofBarodaDiamondandimmortalizedtheline"Diamondsareagirl’sbestfriend."

• Eachyear,theSuperBowl,WorldSeries,andNBAChampionshipringsaresetwithdiamonds.AttheannualGoldenGlobeandAcademyAwardsceremonies,Hollywoodblazeswithdiamonds.

• In2002,BenAffleckpopularizedfancycolorswhenhegaveJenniferLopezanengagementringsetwitha6-caratpinkdiamond.

remarkable Diamonds • TheCullinanDiamondwasthelargestauthenticatedgem-qualityroughdiamondthathasyetbeen

discovered.Thecrystalweighed3,106.75carats–about11/2pounds–andmeasured2x21/2x4inches.ItwasfoundinSouthAfricain1905,andwaspresentedtoBritain’sKingEdwardVIIin1907.ThebiggestgemfashionedfromtheCullinanweighs530.20carats.CalledtheGreatStarofAfrica(orCullinanI),andconsideredtheworld’slargestcutdiamondoffinequality,itispartoftheBritishCrownJewels.

• TheGoldenJubileeistheworld’slargestgem-qualitycutdiamond.Itweighs545.67carats–alittlemorethan33/4ounces–andhasadeepyellow-browncolor.Theroughweighed755.50carats.ItwasdiscoveredinSouthAfricain1986,andwascutsoonafterward.In1996,agroupofThaibusinessmenpurchasedthediamondandpresentedittoKingRamaIXofThailand,tocommemoratehisGoldenJubilee.ThediamondisnowapartofThailand’scrownjewels.

• TheHopeDiamondisoneoftheworld’smostfamousgems.Ithasadarkbluecolorandweighs45.52carats.MostauthoritiesbelievethediamondwasminedinIndiaandcametoEuropeinthe1600s.ItwasnamedforHenryPhilipHope,whopurchaseditin1830.LaterownersincludedFrenchjewelerPierreCartier,AmericansocialiteEvalynWalshMacLean,andrenowneddiamonddealerHarryWinston.In1958,WinstondonatedtheHopeDiamondtotheSmithsonianInstitution,whereithasbeenafavoriteexhibiteversince.

DiaMOnD MagiC anD rOManCe

Diamond is the hardest material in the world and is also very tough. Its name comes from the Greek word “adamas” meaning “unconquerable.”

The Diamond Course Compendium 35

DUraBiLiTY anD Care

DURABILITYAND CARE

factors in Care • Durabilityistechnicallydefinedasagem’sresistancetodamage.Thisimportantattributedepends

onthecombinationofthreeseparateproperties–hardness,toughness,andstability.—Hardnessisresistancetoscratching.Diamondisthehardestmaterialknown,butifdiamonds

rubtogethertheycanscratcheachother.Theycanalsoscratchorcutintojewelrymetalsandothergems.

—Toughnessisresistancetobreaking.Diamondsareverytough,butadiamondcanbreakifitreceivesasharpblowinjusttherightdirection.Lessseveredamage,intheformofchipping,canalsooccur.

—Stabilityisresistancetodamagefromheat,temperaturechange,intenselight,orchemicals.Undermostcircumstancesdiamondsareexceptionallystable.However,anintenseflamecanburnadiamond.Highheatandstrongchemicalscanalsodamagesometreateddiamonds.

guidelines for Care • Adiamondcanbewornandenjoyedforalifetime,andstillshowallitsbeauty,butitrequires

propercaretodoso.• Inchoosingdiamondjewelryforwearability,therearefourmainthingstoconsider–thetypeof

jewelry,thesettingstyle,andthematerialsfromwhichthejewelryismade,andthekindofwearthat’sexpected.

36 The Diamond Course Compendium

—TypeofJewelry–Rings,bracelets,andcufflinksaregenerallymoreexposedtobumpsandscrapesthanearrings,pendants,pins,andtietacks.Forsomeonewhohasanactivelifestyle,oneofthesaferchoicesmaybebest.

—SettingStyle–Thisisespeciallyimportantforrings.Bezelandgypsysettingsprovidemaximumprotection.Tiffany-typeprongsettingsdramatizediamonds,butrequiremorecarefulwear.Tensionsettingsanddinnerringsmaybebestreservedforspecialoccasions.

– ExpectedWear–Akeyquestionis:Whereandhowoftenwillthejewelrybeworn?Therearebigdifferencesbetweentheforms,styles,andmaterialsthatareappropriateforspecialoccasionsandthosethatwillstandupwellforfrequentofficeorcasualwear.

• Rulesforroutinewearandcare:—Whengettingdressed,putondiamondjewelrylast–aftercosmeticsandfragrances.

—Neverweardiamondjewelrywhiledoinghouseholdchores,gardening,homerepairwork,etc.

—Avoidlettinggold-and-diamondjewelrycomeincontactwithchlorinefromsourceslikecleansers,bleach,andswimmingpoolorhottubwater.

—Ifengagementandweddingringswillbeworntogether,considersolderingtheshankstogethertopreventthemfromrubbingagainsteachother.

—Whenjewelryisnotbeingworn,itshouldbestoredsomeplacesafe.Cloth-orplush-linedjewelryboxeswithindividualcompartmentsareideal.Apouchorcushionedboxprovidedbythejewelercanalsobeused.

—Neverstorejewelrybywrappingitinfacialtissue.Tissuethatappearstobewaddedupmaybethrownaway,takingthejewelrywithit.

• Astimegoesby,keepaneyeondiamondjewelrytobesurethesettingsarenotbecomingwornandthediamondsarenotloose.Jewelryshouldbeprofessionallyinspectedandcleanedeverysixmonths.Itshouldbetakeninimmediatelyiftherearesignsofdamage.—Materials–Itiseasiertodamagethemetalthatholdsadiamondthanthediamonditself.High

karatgoldalloys–like18K–havearichlook,butarerelativelybendableandeasilyscratched.Formostpeople,14Kisamorewearablechoice,especiallyinringsandbracelets.Withitsgreatstrength,platinumisalsoanexcellentoption.

• Themostconvenientdeviceforat-homejewelrycleaningisaconsumerversionoftheultrasoniccleanersprofessionalsuse.Commercialjewelry-cleaningsolutionsalsoworkwellfordiamonds.However,ultrasonicsandcleaningsolutionscandamagesomecoloredgems.

• Thesafestall-roundcleaningmethodfordiamondsandothergemsisgentlescrubbing.Forthis,useasofttoothbrushwithamixtureofwarmwaterandmilddetergent.Afterwashing,thepieceshouldberinsedinfreshwateranddriedwithaclean,soft,lint-freecloth.

• Agoodcleaningscheduleisatleastonceaweekwithtouchupsforspecialoccasionsoranytimetheyareneeded.Justbeforecleaning,thepieceshouldbeinspectedforunexpectedwearordamage.Iftherearesignsofthese,thepieceshouldbetakentoaqualifiedjewelerbeforeitiswornagain.

DUraBiLiTY anD Care